For inductively hardening the bearings of a crank shaft it is standard as described in German patent 3,836,268 and U.S. Pat. No. 3,967,089 to mount the crankshaft in a workpiece holder that typically has a headstock and tailstock for gripping the crankshaft and rotating it in a work space about its bearing axis. A transformer supplies alternating current to an inductor that is shaped to fit around the bearing of the rotating workpiece. The inductor can be moved axially and also radially of the workpiece's rotation axis so that it can be fitted with the bearings one after the other to inductively heat them in a standard hardening operation, often followed by quenching with a liquid.
The transformer serving as power supply for the inductor has a primary connected to line and a secondary connected to the inductor. Since the wattage applied to the inductor is very high, this transformer is relatively massive.
This power supply is mounted in the slide or carriage that also carries the inductor, or a fitting that can be hold any of a plurality of inductors differently shaped for bearings of different diameters and/or axial lengths. This slide must be moved along the crankshaft from bearing to bearing so the inductor can do its job, which requires that the slide have a very precise and strong actuator to ensure fast and accurate positioning. Hence the entire slide assembly, which includes the power transformer, and its actuator are very massive.